The molecular formula for octane is C8H18. Calculate the molar mass of the empirical formula of octane. 114.432 g/mol 228.464 g/mol 57.116 g/mol 14.279 g/mol
The Correct Answer and Explanation is:
To find the molar mass of the empirical formula of octane (C8H18), we first need to determine its empirical formula.
Step 1: Determine the Empirical Formula of Octane
The molecular formula for octane is C8H18. The empirical formula represents the simplest whole-number ratio of atoms of each element in the compound.
To find the empirical formula, divide both subscripts of the molecular formula by the greatest common factor of 8 and 18, which is 2. Thus, the empirical formula of octane is:Empirical formula of octane=C4H9\text{Empirical formula of octane} = \text{C}_4\text{H}_9Empirical formula of octane=C4H9
Step 2: Calculate the Molar Mass of the Empirical Formula
Next, calculate the molar mass of the empirical formula, C4H9. The molar mass is the sum of the atomic masses of the elements in the empirical formula. The atomic masses (rounded) are:
- Carbon (C) = 12.01 g/mol
- Hydrogen (H) = 1.008 g/mol
Now, calculate the molar mass:Molar mass of C4H9=(4×12.01)+(9×1.008)\text{Molar mass of C}_4\text{H}_9 = (4 \times 12.01) + (9 \times 1.008)Molar mass of C4H9=(4×12.01)+(9×1.008)Molar mass of C4H9=48.04+9.072=57.112 g/mol\text{Molar mass of C}_4\text{H}_9 = 48.04 + 9.072 = 57.112 \, \text{g/mol}Molar mass of C4H9=48.04+9.072=57.112g/mol
Step 3: Conclusion
The molar mass of the empirical formula of octane (C4H9) is 57.116 g/mol. Therefore, the correct answer is:
57.116 g/mol.
